Backyard Aquaponics
A place to discuss aquaponics

Hi APers,

I just finished setting up my first AP system. It consists of a 220l FT and about 0.7 sq meters of GB in a small custom green house. I am just starting the fishless cycling process using 5% ammonia. The water temperature is currently at around 17C.

My main question today is regarding water Ph. The water Ph coming out of the city faucet is at 8.0 using a standard API High Ph test. From a ph perspective, I did a control test of some water coming out of my neighbors ground well pump and that was around 6.4. Mineral water from the supermarket was at around 7.4.

My question is if I should do something immediately to bring the Ph of the water down? I added ammonia about 7 days ago. Unfortunately I over did it a bit at 4ppm but it is now at 0.5ppm with the Nitrites at 5ppm and Nitrates at 20ppm. Everything seems to be going in the right direction.

I have read however that the Ph should be below 7.2 or so before adding any starter veggies. I have some plants from my summer veggie garden I was planning on transplanting in the media when the system is ready.

My questions to all are as follows:

1. What is the Ph of the city water for different locations around the world. I am especially interested in any measurements from the Netherlands, Belgium, Germany or the UK.

2. What is the best way to bring my PH down to 6.8/7.0? My criteria is something organic that is safe for plants and fish and hopefully easy to source in Northern Europe.

3. How long would it normally take before I should see the Nitrites fall? To what extent will water temperature be affect Ph or the nitrogen cycle? If I heated the tank up to 20 for the fishless cycling, would this make a big difference? Keep in mind that we are going into fall and I would like to target water temperature at around 16-18C in the greenhouse.

Any comments, opinions, etc on this matter is greatly appreciated!

Mark
Utrecht, The Netherlands

My system is 2 years old and ph has never been below 8. They say it will drop eventually, but I have never seen it. Put your plants in, doesn't seem like the high ph is effecting my plant growth.

When I was in the UK my tap water was 7.6,
Hydrocloric Acid,you won't need much in your system to bring the PH down,you could use you neighbours well water as your top up,add a known amount to a known amount and see what it does to the PH,you know then what your top up will do to your system. Optimum PH for ammonia oxidisers is 7.8-8.0, nitrite oxidisers 7.3-7.5.
It's well on it's way down now,as you ask about Temp it has a profound effect on the nitrifying bacteria,if you heat your tank and with your high PH things will happen that much quicker. .
Optimum temps are 25-30 degres C, they die at 0 or high 40s.

You can plant you system with veggies but keep a lookout for iron deficiency. The iron is not available at high Ph, see below chart;



In this case you could add some chelated iron.

If the iron isn't available because of high PH,adding chelated iron will only add to the already not available iron,until the ph comes down,as you can see from your chart will this iron be a available.

Thanks everyone for the replies.

I ended up "borrowing" 90l of my neighbors ground/well water and replaced it in the tank. It is now at 7.4. Also turned up the heater and placed the AP system in a mini green house. Curious to see if my Nitrites will drop over the next week or so....

Just a quick update on the fishless cycling.

In addition to the 90l of lower ph well water, I also added an aerator and turned up the pond heater so the water is now around 21C.

The end results is that the system can rather quickly absorb 15ml (3 teaspoons) of 5% ammonia in 220l in 48 hours where the measurement goes from 2ppm to 0.

The Nitrites are still a bit slow to be consumed and are hovering at 2ppm. The good news is that the Nitrates have gone up from around 20ppm to somewhere between 40-80ppm (colours are hard to read).

Looking forward to adding some starter goldfish the weekend after next.